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Kondo spin liquid and magnetically long-range ordered states in the Kondo necklace model

Guang-Ming Zhang·Qiang Gu·Lu Yu
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Abstract

A simplified version of the symmetric Kondo lattice model, the Kondo necklace model, is studied by using a representation of impurity and conduction electron spins in terms of local Kondo singlet and triplet operators. Within a mean field theory, a spin gap always appears in the spin triplet excitation spectrum in 1D, leading to a Kondo spin liquid state for any finite values of coupling strength $t/J$ (with $t$ as hopping and $J$ as exchange); in 2D and 3D cubic lattices the spin gaps are found to vanish continuously around $(t/J)_c\approx 0.70$ and $(t/J)_c\approx 0.38$, respectively, where quantum phase transitions occur and the Kondo spin liquid state changes into an antiferromagnetically long-range ordered state. These results are in agreement with variational Monte Carlo, higher-order series expansion, and recent quantum Monte Carlo calculations for the symmetric Kondo lattice model

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Guang-Ming Zhang, Qiang Gu, Lu Yu. 2000-04-06. Kondo spin liquid and magnetically long-range ordered states in the Kondo necklace model. https://doi.org/10.1103/physrevb.62.69

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